Problem: If $x \oslash y = x+3y$ and $x \triangleright y = (5-x)(y)$, find $-6 \oslash (3 \triangleright -4)$.
Explanation: First, find $3 \triangleright -4$ $ 3 \triangleright -4 = (5-3)(-4)$ $ \hphantom{3 \triangleright -4} = -8$ Now, find $-6 \oslash -8$ $ -6 \oslash -8 = -6+(3)(-8)$ $ \hphantom{-6 \oslash -8} = -30$.